Philips 220B4LPCB/00, Service Manual

Page: 16 / 86

!
!
Meridian 3
16
5.2 Pow
e
r Board
EMI Fi
lte
r
Circuit
In
put
AC
S
our
ce
Inr
us
h
Preven
tion
Rectification
Main Tran
sfo
rme
r
Switc
hi
ng
Circui
t
( PW
M C
ontr
ol
IC
&
M
O
SF
ET
)
Rectification
Fe
edba
ck
Contr
ol
Circuit
B+
Diode
Rectifie
r
an
d
Fi
lter
Ci
rcui
t
O
utp
ut
(+
5V
) To
M
ain
boa
rd
/A
ud
io *
2W
Fus
e For
O
LP
Diode
Rectifie
r
an
d
Fi
lter
Ci
rcui
t
Out
pu
t
(+
16
V)
To
USB(Option)
Circui
t
Diode
Rectifie
r
an
d
Fi
lter
Ci
rcui
t
PWM
Control Circ
uit
CONVERTER L
D
7750
RGR
Dri
ver Ci
rcu
it
( F
ull
Bri
dge )
LED Pa
nel
A
bn
orma
l Pr
ote
ct
Contr
ol C
irc
uit
Feed
back C
on
tr
ol
Circuit
Di
mmi
ng
Contr
ol
Circuit
O
N
/ OF
F C
on
tr
ol
Si
gna
l
( 16v: on
/ 0v:o
ff )
Dimmin
g
C
ontr
ol
Si
gna
l
(Burs
t mo
de
l Si
gna
l )
A
dapter
Bl
ock Ci
rc
ui
t
Conver
ter
Block Cir
cuit